// returning nil instead of empty slice if all spaces.
		return nil
	}
	return s[start:stop]
}

// Runes interprets s as a sequence of UTF-8-encoded code points.
// It returns a slice of runes (Unicode code points) equivalent to s.
func Runes(s []byte) []rune {
	t := make([]rune, utf8.RuneCount(s))
	i := 0
	for len(s) > 0 {
		r, l := utf8.DecodeRune(s)
		t[i] = r
		i++
		s = s[l:]
	}

	}
}

func bmIndexRuneUnicode(rt *unicode.RangeTable, needle rune) func(b *testing.B, n int) {
	var rs []rune
	for _, r16 := range rt.R16 {
		for r := rune(r16.Lo); r <= rune(r16.Hi); r += rune(r16.Stride) {
			if r != needle {
				rs = append(rs, rune(r))
			}
		}
	}
	for _, r32 := range rt.R32 {
		for r := rune(r32.Lo); r <= rune(r32.Hi); r += rune(r32.Stride) {
			if r != needle {
				rs = append(rs, rune(r))

}

// append single byte to scratch buffer
func (s *scratch) add(c byte) {
	if s.fill+1 >= cap(s.data) {
		s.grow()
	}

	s.data[s.fill] = c
	s.fill++
}

// append encoded rune to scratch buffer
func (s *scratch) addRune(r rune) int {
	if s.fill+utf8.UTFMax >= cap(s.data) {
		s.grow()
	}

	n := utf8.EncodeRune(s.data[s.fill:], r)
	s.fill += n
	return n

// Unicode code points satisfying f(c).
// The iterator yields the same strings that would be returned by FieldsFunc(s),
// but without constructing the slice.
func FieldsFuncSeq(s []byte, f func(rune) bool) iter.Seq[[]byte] {
	return func(yield func([]byte) bool) {
		start := -1
		for i := 0; i < len(s); {
			size := 1
			r := rune(s[i])
			if r >= utf8.RuneSelf {

		ret := csv.NewReader(r)
		ret.Comma = []rune(args.FieldDelimiter)[0]
		ret.Comment = []rune(args.CommentCharacter)[0]
		ret.Quote = []rune{}
		if len([]rune(args.QuoteCharacter)) > 0 {
			// Add the first rune of args.QuoteCharacter
			ret.Quote = append(ret.Quote, []rune(args.QuoteCharacter)[0])
		}
		ret.QuoteEscape = []rune(args.QuoteEscapeCharacter)[0]
		ret.FieldsPerRecord = -1

		Short: "Open Prometheus web UI",
		Long:  `Open Istio's Prometheus dashboard`,
		Example: `  istioctl dashboard prometheus

  # with short syntax
  istioctl dash prometheus
  istioctl d prometheus`,
		RunE: func(cmd *cobra.Command, args []string) error {
			client, err := ctx.CLIClientWithRevision(opts.Revision)
			if err != nil {
				return fmt.Errorf("failed to create k8s client: %v", err)
			}

	r.i--
	return nil
}

// ReadRune implements the [io.RuneReader] interface.
func (r *Reader) ReadRune() (ch rune, size int, err error) {
	if r.i >= int64(len(r.s)) {
		r.prevRune = -1
		return 0, 0, io.EOF
	}
	r.prevRune = int(r.i)
	if c := r.s[r.i]; c < utf8.RuneSelf {
		r.i++
		return rune(c), 1, nil
	}
	ch, size = utf8.DecodeRune(r.s[r.i:])
	r.i += int64(size)
	return
}

			if (len(args) == 1) != (configDumpFile == "") {
				cmd.Println(cmd.UsageString())
				return fmt.Errorf("cluster requires pod name or --file parameter")
			}
			return nil
		},
		RunE: func(c *cobra.Command, args []string) error {
			kubeClient, err := ctx.CLIClient()
			if err != nil {
				return err
			}
			var configWriter *configdump.ConfigWriter
			if len(args) == 1 {

// converted to int they correspond to the rune size that was read.
type readOp int8

// Don't use iota for these, as the values need to correspond with the
// names and comments, which is easier to see when being explicit.
const (
	opRead      readOp = -1 // Any other read operation.
	opInvalid   readOp = 0  // Non-read operation.
	opReadRune1 readOp = 1  // Read rune of size 1.
	opReadRune2 readOp = 2  // Read rune of size 2.

	fmt.Println(bytes.LastIndexFunc([]byte("go gopher!"), unicode.IsNumber))
	// Output:
	// 8
	// 9
	// -1
}

func ExampleMap() {
	rot13 := func(r rune) rune {
		switch {
		case r >= 'A' && r <= 'Z':
			return 'A' + (r-'A'+13)%26
		case r >= 'a' && r <= 'z':
			return 'a' + (r-'a'+13)%26
		}
		return r
	}